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How to Make a Big Batch of Kombucha

About: Tim Anderson is the author of the "Heirloom Technology" column in Make Magazine. He is co-founder of www.zcorp.com, manufacturers of "3D Printer" output devices. His detailed drawings of traditional Pacific...
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Kombucha is a fermented tea beverage popular in Russia, China, and elsewhere. The culture forms a leathery skin called the "mother" that floats on top.This week's Instructables TV episode shows how to wrangle the jellyfish-like "Mother" and make Kombucha 5 gallons at a time. This method produces a fizzy carbonated kombucha that tastes very much like hard apple cider.

For background on this bizarre beverage, read Arwen's Making Kombucha Instructable and the Wikipedia Kombucha article. Some confusion arises from the existence of a Japanese kelp tea also called "kombucha".

Back to the blob:For me it all started when my friend Anne Harley went to Russia, made herself fluent in the language, joined a band of gypsy musicians, and went on tour with them.Did you know Russian Gypsies have a caste system that dates back to their origins in India?That was news to me. So was the fact that Kombucha exists. Anne brought a very fine Kombucha culture back with her and taught me how to make it.

Since then I've made hundreds of gallons of Kombucha for my friends and myself. I've done a great deal of experimentation and had some serious mishaps. I've killed the culture several times, coaxed it back when it got out of balance, and had a couple of explosions that splattered kombucha far and wide and could have seriously injured someone.Between the mistakes, mishaps and disasters, actual Russians and new-age fruitcakes have tasted my Kombucha and told me it's the best they've ever had. I work with my culture until I get it tasting like apple cider. So much so that you'll try to figure out what varieties of apples it's from. But there's really nothing in it but tea, sugar, and a festering mass of microbes.

We'll be going step-by step through the process later, but for reference, here is how to make the sweet tea to be fermented.

Step 1: Get a Pound of Tea Leaves

Don't ever use Earl Grey tea. The bergamot in it will injure your culture and you'll need to get a new starter. This has happened to me. Anything with citrus in it is bad.

Buy your tea in Chinatown or an Indian grocery store. I pay between a dollar and four dollars for a pound of tea, which will make two or more 5 gallon batches. I've bought many a 6lb bag of tea, which is very satisfying, walking out with a couple of suitcase-sized bags of tea.

Assam tea, Mamri, or Green tea such as "Special Gunpowder" are safe choices."Pu Er" tea smells pretty bad at first but makes good kombucha. (The name Pu Er is actually English, get it? "Poo Air" :) )Don't risk your whole culture with saffron tea, but it can turn out ok.Early in the fermentation process you'll be able to clearly taste what type of tea it is, but when the fermentation is more advanced the apple flavors of kombucha will dominate and the flavor of the tea leaf recedes.

Don't use teabags. You'll be shucking them for hours, dealing with lots of teabags and unsure of how strong your tea really is. You'll also not know for sure what's in the teabag, maybe something as bad as Earl Grey.

Here's my giant teabag, which I made from a piece of cotton bed sheet.

Types of Tea that have worked for me:AssamMamriGreen (very slow unless you use some brown sugar)Jasmine (marginal)Coffee (eventually it barely tastes like coffee)

Star likes herbal teas, and has successfully tried:Peppermint (mother was depressed for a long time, but eventually rallied)Peppermint-ChamomileChamomile-Echinacea

Step 2: Brew Much Tea

Warning: The tea MUST COOL before you add the culture. The culture you have has evolved at room temperature. If you put it in warm tea certain species such as lactobacillus will outbreed the others and you'll get a sour kombucha without well developed fruit flavors. Very much like commercial kombucha, which is usually a weak vinegar.

Brew a gallon or two of very strong tea, then dilute it.Don't boil all five gallons of water. That wastes energy and time and improves nothing.Put one or two cups of dry tea in the giant teabag, tie it shut and boil it in your biggest pot."one OR two cups?" you say? Why not more precision?

The recipe calls for 1.5 cups, but all tea is not the same. That's okay because large batches like this are much more forgiving of variations than small batches. If you make a gallon or less you must stick exactly to the recipe in order to get a good result:

If you've got a big thermos, you can let it steep there hot as long as you wantYou could also use a hay box or make Arwen style sun tea.

Step 3: The Giant Teabag Workout

Wring out the giant teabag into your brewing bucket, soak it with water, repeat until you don't feel bad about throwing out or composting such a large amount of used-up tea leaves. That 1.5 cups of dry tea swells up to become quite an impressive mound.

I cut the top off a plastic springwater carboy to make the brewing bucket seen here.
I'm in the process of kneading the last tea-essence out of the teabag.
Actually that's impossible, but you have to give up sometime.

Step 4: Coffee Screen Method

You can also skip the teabag.
Throw the leaves right in the water and strain them out afterward.
Here I'm pressure-cooking the tea and then pouring it through a gold screen coffee filter.
This is Mamri tea which stays as little pellets that don't clog the filter. Leaf tea and things with large flakes like "Special Gunpowder" would probably clog the screen and take longer than the big teabag.

I usually soak and pour several times, but it still probably doesn't extract as much tea-stuff as the big teabag method.

Step 5: Dilute and Add Sugar

This is fun. Open a new 5 pound bag of sugar and dump most of it in. All except 10 or 15% of it.

White sugar is fine, except green tea ferments very slowly unless you add some brown sugar with the white. Otherwise it will take way too long. Other kinds of tea don't need brown sugar but I usually throw some in anyway. Black tea is just green tea that's been through an oxidation process. That seems to make it easier for the mother to digest.There's nothing wrong with using just brown sugar except it costs more in the U.S. and the flavor will be a little different. Use whatever sugar gives you the flavor you like.

Add cold water to make it five gallons and mix it all up.If your batch is bigger than your containers split it into multiple containers as seen here.

While you're at it, open a bottle from your previous batch of fizzy kombucha from the fridge and drink it from a fishbowl with ice as seen here. Ahhh good.

Sweeteners that have been reported to work:Agave nectarPineapple JuiceHoneyBrown SugarWhite Sugar

Step 6: Add Mother

When the tea has cooled, add the mother. Try to get a solid layer to float on top. That saves time. I save all my mother and add all of it to the new batch.
It grows by a quarter or half inch with each batch and would soon leave no room for tea, but lots of people ask for starters so it's not a problem. I can get starters from them if I make a mistake and mess up my culture, so I don't need to hold any in reserve.

I like lots of mother working. Some people want to only have a single layer of mother and will split the top surface off with each generation. They call the new layer "the daughter" and use it to brew their next batch. If you do that you'll need to add some liquid kombucha or vinegar to your new batch to make it acidic early on and avoid spoiling.

The mother is porous and vinegary. In the quantities seen in these pictures, it will innoculate the new batch thoroughly and leave no ecological niche for opportunistic foreign organisms.

New mother will grow only at the surface.
If part of the mother sinks, a new skin will grow across the area of exposed liquid at the surface.
In this picture you can see that the old darker colored mother had puddles of liquid on top of it. The new lighter colored areas grew there.

Step 7: Cover With Cloth. NO LIDS!!!

Warning: NO LIDS! You must cover the vat with cloth.

If you have a lid over your vat, even a loose one, there will be moist air over the mother. There will be condensation on the lid and sides of the vat above the mother.
Mold will grow there and spread to the mother. The mother will die and possibly break apart.

If you see fuzz on the mother throw it away, clean all your vessels and let them dry out.
Bleach them or leave them in the sun if you want to be really careful.
Be very alert to this. Some types of mold make poisons.
Mold is dangerous, which is to say people have died from it.

The Russians call "the mother" "the mushroom", but there is no actual mushroom, fungus or mold in this complex community.

In my experience with helping people get started, mold is a bigger problem in California than in New England.

If you want to brew in a carboy (big jug with narrow neck, such as spring water vendors use) , you need to cut the top off so it's more like a bucket or vat.
I've seen it attempted in standard carboys and it ends badly, even if the jug is covered with cloth rather than a cap.

This fermentation is complex process controlled by the mother. It's an aerobic process at least on the surface layers, and the vessel should not be sealed or you'll end up with problems.

There will be another anaerobic stage later for those of you who want more fizz.

Step 8: Date the Vat

Write the date on the vat. Don't expect to remember how long it's been in there.
I expect this batch to be ready for bottling in 9 days or so.
Variables in how much time it takes are type of tea (green or black), type of sugar (white or brown)
how much mother there is, vitality of mother, temperature (warm makes it not tasty, but it gets not tasty in a hurry).

Step 9: Sit Back and Watch the Show

A few days have gone by and good things are happening.
In this photo I've pulled back the cloth for a better view.

A new layer of skin is beginning to form at the surface of the liquid.
Where the old mother touches the surface it will be attached to that.
This layer of skin controls the environment in the vat.

The tea has gotten a little lighter in color and cloudy.
Small bubbles of carbon dioxide are forming in the liquid and under the flaps of mother.
Occasionally they blurp up from under the mother. That's yeast working, making alcohol and acetic acid vinegar.

Some tentacles are starting to form, hanging down from the mother.
I don't know what they are but they seem to make the apple flavor. A very good sign.
The tentacles are structurally very different from the mother.
They look almost like algae and are very weak. They're usually darker than the tea and just vaguely greener.

A dusty layer is appearing on the bottom of the vat. I believe it's largely lactobacillus. It's making lactic acid vinegar. It has the sharp tangy flavor found in yogurt and sauerkraut. It's good for you and should be bottled with the rest. Don't transfer it to the next batch or that flavor will dominate.
The same thing will happen if your vats aren't kept cool enough. To correct a culture that's gone sour and simple, wash the vessels and mother with water. Get some starter from someone who's getting more flavors.

The yeast in the vat gets oxygen it makes sugar into alcohol then acetic acid vinegar.
That acid has a boingy sort of tangyness to it which is different from the sharp straightforward tang of acetic acid.
When it gets less oxygen the yeast makes sugar into alcohol, which in small amounts gives the other flavors a sense of depth and buoyancy. In larger quantities it's just alcohol.

Step 10: Apple Tentacles

Here are the tentacles that seem to make an apple taste.
I brewed recently after letting the mothers sleep in their own juice for a long time. There were no tentacles and the k'cha had no apple taste. But a bottle of it tasted very apple-icious a few weeks later. I looked and tentacles had grown in the bottle.

Carbonation bubbles float the tentacles to the surface when you disturb the liquid or pull the mother off. 2nd photo shows what it looks like when it floats to the surface.

Step 11: Dusty or Cloudy

The dusty sediment building up at the bottom could be Acetobacter, Lactobacillus, or Yeast.
It's probably a mix of those.
It seems to correspond more with the "straight" sour taste of lactic acid than the "boingy" sour taste of acetic acid.

I try not to transfer this sediment between batches. The flavor seems to be best if these species have to regenerate from the mother. Mostly I look for the tentacles in the previous step, and pay attention to what conditions favor those. Don't let your brew get warm, that favors the sour critters in this sediment rather than the tasty tentacles.

I must have been hasty and transferred this sediment. The bulk of the liquid is clear, not cloudy, so it's a few days away from bottling at least and I wouldn't expect this much sediment from liquid this clear.

Step 12: Cloudy Means Ready

This stuff is ready to taste and bottle.
The bubbles mean a somewhat anaerobic environment in the liquid and the yeast is making C02 and a bit of alcohol. That stirs up the sediment and makes it cloudy.

There's a nice growth of tentacles, so it's likely to be tasty!

Step 13: Vegan Leather Anyone?

The mother is surprisingly tough and solid like squid.
I tried pretending it was calamari and fried it but it wasn't very good.
Then again my fried calamari isn't very good either. Maybe squid isn't supposed to be fried.

Small chunks of mother can be drunk in kombucha and are really good, like the Chinese "pearl" drinks.
The mother chunks are slightly more tart than the kombucha they inhabit.

To get a really thick and solid mother, just let a batch of kombucha keep fermenting. It'll get really sour and you'll get comments about the smell. You'll ignore the comments because it smells good to you. The longer you wait the more sour and vinegary your kombucha becomes, and the better the mother grows.

I tried drying the mother, it gets much thinner and very tough like parchment or rawhide.
I've read that it's been used to make shoes in wartime, but have been unable to find any more details than that.

Step 14: Ready to Drink, But ...

You can start drinking your kombucha now if you want to.
Some people take out a portion to drink every day and replace it with an equal quantity of sweet tea.

That is a traditional method but requires regular habits.

Also I like it more fizzy than it gets in the vat, which means bottling it.

Step 15: Look for Bottles

When it's just the way you want it, or rather ALMOST, it's time to put it in bottles.
I say ALMOST because you should bottle it when it's just a little too sweet.
That's so the yeast can make that extra sugar into fizz and just a little alcohol.

Regular PTFE or PET type plastic soda bottles, plastic spring water bottles or anything like that are fine.

I once had fifteen gallons exactly ready for bottling and couldn't find any bottles to put it in.
My friends had found my collection of empty bottles and destroyed them in a fenzy of inventiveness,

So I put it in carboys with rubber glove vapor traps as shown here and let the yeast work while I spammed the institute for empty soda bottles.

You can blend old sour kombucha, young sweet kombucha and water to adjust the flavor when you bottle it.
Set the bottles them aside til they get hard from carbonation.
Put them in the fridge
drink it.

WARNING
If you wait too long to drink it the bottles can explode from excessive carbonation.
They can puff up til the soda bottle is round on the bottom and rings like a bell when you tap it.
Three of mine got like this and blew up at once. They blew the side out of the rubbermaid tub they were in, splattering kombucha all over the ceiling, and making a very loud noise.

This danger is why commercial kombucha can't be as good as the stuff you make yourself.
Commercial bottlers can't be blowing fingers off their customers, putting their eyes out and deafening them by shipping time-bomb beverages.
They have to terminate yeast fermentation in the bottles.
That means high acid, low sugar, or dead culture.

If you do it at home you get to have it all.
Sugar, live culture, carbonation, and a potentially dangerous bottle that could blow up if you don't drink it in time. Don't use glass bottles. Enjoy!!

Step 16: Bottling Jug

I cut the top off this waterjug and drilled a hole by the bottom for a plastic spigot.
I pour the new k'cha in here from the brewing vats. If it's too strong i add water.
Be aware that the sweet taste recedes faster than the sour taste as you dilute.

If you lost track of time and your brew got way too sour, you can save it a bit at this step.
You can add water and sugar, or younger sweet brew.
If you add sugar though you'll need to leave it in the bottles longer before it tastes honest.

New sugar will make your teeth hurt just like candy or soda.
After the mother has lived on it for a while, it still tastes sweet, but it won't make your teeth hurt anymore.

I used to screen my brew before bottling, but now I like the chunks and tentacles. Like an Asian "pearl" or "bubble" drink. When this spigot gets clogged by that stuff I just work the lever until the chunk comes through.

Step 17: Decant Over-Fizzed K'cha

The bottles will keep fermenting and carbonating until something stops them.
That could be running out of sugar, building up too much alcohol, acetic acid, lactic acid, or exploding.

This is why store-bought kombucha can never be as good as stuff you make yourself. They'd get sued when a forgotten bottle blew up and hurt someone. So they have to make it sour and not sweet. That way fermentation terminates or gets very slow and they can even put it in glass bottles.

I've seen plastic bottles of home brew k'cha puffed up round with no necks or puckers on the bottom. They ring like a bell if you tap them, and it's scary dangerous. Use bomb squad methods to deal with bottles like that. Three of mine once went off in a daisy-chain. They blew the side out of a rubbermaid bin and put dripping splatters all over the ceiling. Bottles like this could cripple, deafen, or blind you.

A more common problem ( opportunity ) is bottles with so much fizz it's hard to open them without champagning k'cha all over the room instead of into a glass.

Here's one way to deal with that. First refrigerate it. Gas solubility is higher in cold water.
Then rapidly open and pour the kombucha into an angled glass. The angled glass and angled bottle present a much larger area surface for the gas to diffuse out. If you set the same bottle vertical, the upper surface is too small and you can get a volcano effect.

If your stuff has too much fizz even for that, we're in the realm of art, devise your own methods.
Freezing is bad. Ice has poor gas solubility and plugs the neck when you open.
Some people like to barely open the cap so a slow hiss of air comes out, too slow for bubbles to erupt. I like to open the cap and instantly squish out the remaining air before the eruption. It's amazing how the bottle re-inflates every time you do that. There can be a huge quantity of gas dissolved in the liquid.

Thanks for the instructable. Pu 'er is not a mispronounced English "poor air"; the tea is named after Pu 'er City (which contrary to popular belief doesn't mean "poor air that smells like s**t"...;-) It is my favorite tea, that's why I have to call you on this.

Tim, I can't wait to taste my batch, which is in its last carbonating stage. How did you work your culture to get it to taste like apple cider? Was it the type of tea you used or the time it fermented? Tips, please?

DO NOT USE GLASS BOTTLES!!!! I HAVE BEEN USING THEM WITH NO PROBLEMS BUT MY DAUGHTER AND I CAME HOME THIS EVENING TO THE SOUND OF BOMBS EXPLODING AND I REALIZED IT WAS BOTTLES OF KOMBUCHA!!!!! FORTUNATELY, NO ONE WAS HURT. I WILL BE USING SOMETHING ELSE. THE TEA WAS NOT EVEN TWO WEEKS OLD.

any fermented product needs to be refrigerated once it is sealed air-tight unless you are absolutely sure that there is no more sugar for the culture to "eat". two weeks is a long time for the pressure in a bottle to build up if the kombucha is still fermenting...if you aren't familiar with the term "specific gravity" then you are best off playing it safe and putting your kombucha in the fridge after a week or so in the bottle...
i would stick to glass though...plastic is toxic!
good luck!

To add to "unless you're absolutely sure there is no more sugar".... at that point it will be officially "Vinegar" and you probably won't want to drink it. Even the lowest carbs form of drinkable Kambucha has sugar (The lowest sugar content you can really have and still have a drinkable product is about 1g/7oz at the time you drink it).

What? Did you seal the damn things?? They need air to breath.. and if you fill them too high the scoby will plug the top shoulder of the jar. I had that happen once but noticed it before too much pressure formed. I use a sun tea jar and I was able to relieve the pressure with the spigot. Glass is the only way to go.

hello friend, thanks for this. I left my mother with an ex co-worker to take care of while I was away and the boss threw it out, and now for the life of me I can't get my hands on another mother mushroom lady. Please help? Could you? That would be divine. Thank you, in advance. Have a fantastic day

Hello! Firstly, thanks for such an awesome tutorial! I have a few questions, if you have a moment.

My background is that I am a beer and meade maker, so I have all of the appropriate equipment for said productions and it is all pretty great quality stuff (glass). I have a 3gal glass carboy that is sitting around not doing anything that I'd like to use to make a batch of k'cha with.

1.) Can I not use it with a standard bubbler on top to allow for gas to escape? I have never noticed condensation forming with the production of beer or meade, so since k'cha requires a cool environment, I don't see how it would produce it with that.

- Or could I use the glass carboy with a coffee filter over the top instead of the bubbler? - Is it the headspace that makes the difference?

2.) What sugars are considered good to use and in what form? - Do any of them, like honey, need to be boiled for a certain time period to break the complex sugar bonds for the mother to process, or is it fine just heating it up? - Can I use a mixture of sugars (namely thinking honey + light brown sugar)? - If just using honey, what amounts would be suggested?

3.) Does the equipment used need to be sterilized like it does with beer making?

I am brewing my 3rd batch of Kombucha and I have some serious concerns. After drinking a ton of the de-facto commercial brand for about 2 months I started having really bad headaches. I have completely stopped, and they have dissipated to some degree, but I've been pondering what happened. I'd like to mention that I own a copy of Alana Pascal's book 'Kombucha - How-To and What It's All About' thought by many to be the definitive book on Kombucha.

My first concern: Mobilization. It is my understanding that Kombucha is very effective at not only helping your liver process toxins much more effectively, but that if you have amassed a good deal of toxins in your system over the years that they can be 'mobilized'. This raises serious concerns for those who might have a sizable quantity of such things as heavy metals like mercury. After being mobilized, they may not be rapidly expelled from your body, as was the case that caused them to build up in the first place, subsequently redistributing in other soft tissue of the body such as the brain. I believe very little is discussed about this the average consumer has no clue just how effective Kombucha can be at mobilizing toxins and super charging your liver. Clearly this is a double edged sword and something that should be regarding in much the same way any sensible person would look at vitamins. Proper dosage is key. It bothers me that commercial products say little about the dangers of over consumption. Given that Kombucha mobilizes so well, it is highly recommended that you DO NOT drink it when pregnant or breastfeeding as the fetus/infant will be subject excessive toxins. It is also discouraged for use by children. I don't want people doing damage to themselves out of ignorance, and I don't want the drink I've grown to enjoy greatly to face regulation or worse.

My second concern: Carbonation and storage. In Alana Pascal's book, she informs that when Kombucha is capped, and anaerobic fermentation occurs, toxic by product is created namely in the form of acetone (think paint thinner or nail polish remover). Acetone is a ketone that is very destructive to the kidneys. She indicates that Kombucha should not be stored capped in the refrigerator for more than an astonishingly conservative 3 days or there is the risk acetone production. This is troubling. Most people will tell you, Kombucha is much more palatable when carbonated. This is where I am uncertain. Small amounts of acetone are present in commercial foods we consume and such trace amounts have been deemed relatively safe. Thinking back, I purchased dozens of bottles of commercially available RAW Kombucha. That means, unpasteurized and while I know there are chemical compounds that can be added which do not kill the culture but prohibit it from continued fermentation, I have serious doubt those would have been used. Of those many bottles, several were near there expiration date, and even more of them when opened exhibited vast over-carbonation. This would seem to indicate that shipping and handling practices during the life of that product did not include continuous refrigeration. Suspecting heavily now that this may have contributed greatly to my headaches. To pasteurize or not to pasteurize. Many of the health benefits remain after pasteurization but it certainly isn't the most desirable option. I'd love to hear thoughts on carbonation options, and the risk of prolonged anaerobic fermentation.

The only thing you can do is ferment it for less time. Make your batch for about 5 days. It'll have less alcohol, but also less of the beneficial acids that we want. It really is such a little amount of alcohol, anyway, I say just make it how you like the taste. http://goo.gl/35zcT